Botulinum neurotoxins (BoNTs) inhibit neurotransmitter release at peripheral nerve terminals. They are serologically classified from A to G, with C/D and D/C mosaic neurotoxins forming further subtypes of serotypes C and D. Cultured primary neurons as well as neuronal cell lines such as PC12 and Neuro-2a are often utilized in cell-based experiments for the toxic action of botulinum toxins. However, there are very few reports of the use of neural cell lines for studying BoNTs/C and D. In addition, the differentiated P19 neuronal cell line, which possesses cholinergic properties, has yet to be tested for its susceptibility to BoNTs. Here, we report the responsiveness of differentiated P19 cells to BoNT/C and BoNT/DC. Both BoNT/C and BoNT/DC were shown to effectively bind to and be internalized by neurons derived from P19 cells. Subsequently, the intracellular substrates for BoNT/C and BoNT/DC were cleaved by treatment of the cells with the toxins in a ganglioside-dependent manner. Moreover, P19 neurons exhibited high sensitivity to BoNT/C and BoNT/DC, to the same extent as cultured primary neurons. These findings suggest that differentiated P19 cells possess full sensitivity to BoNT/C and BoNT/DC, thus making them a novel susceptible cell line for research into BoNTs.